As a wireless communication system for improving a transmission rate by spatial multiplexing, or for improving reliability by a diversity effect using different propagation characteristics of a plurality of paths, a MIMO (Multiple Input Multiple Output) communication system has been proposed. In the MIMO communication system, for example, a wireless base station including a plurality of antennas can simultaneously transmit data to a plurality of mobile terminals by using the plurality of antenna. The wireless base station may select a communication-target mobile terminal (or communication-target mobile terminals) from the plurality of mobile terminal. Namely, the wireless base station may perform user scheduling process. Thereby the wireless base station may perform communication (i.e. data transmission and data reception) with the mobile terminal.
Patent document 1: Japanese Patent Application Laid Open No. 2007-20188